1. Field of the Invention
This invention relates to a kit by which an existing motorcycle clutch can be adapted to give it structure affording lighter touch engagement and disengagement, more secure engagement (that is, better gripping power) and generally quieter operation.
2. Description of Related Art including Information Disclosed under .sctn..sctn.1.97 to 1.99
Since 1936 the Harley Davidson "Big Twin" FLH motorcycle has had a dry clutch of the axial-engaging multiple disc-type having a drive or drive cylinder shell with a bearing in one end and a driven or output hub in the bearing. A circular array of studs and pins has extended into the shell from the hub, the studs being parallel to the axis of the shell. The shell has bolted-on inward keys, also parallel to the axis and alternating drive and driven discs in the shell, the drive discs of bare metal have had notches in their perimeters adapted to receive respectively the keys. A compression plate which is spring biased toward the discs compresses the discs together when the clutch is engaged so that the rotary movement of the shell is communicated to the hub; Means are provided to move the compression plate away from the discs against the spring bias to disengage the clutch.
While the above arrangement was used on Harley Davidson motorcycles from about 1936 to 1984, there has been basis for complaint in the performance. For one thing, the driven discs have been of metal and have extended all the way to the inside periphery of the shell. As a consequence, when the clutch is disengaged, the discs being relatively free, have vibrated inside the shell against the keys causing an unacceptable rattling noise. In addition, there being a relatively small number of discs, engagement of the clutch has required strong springs between the spring collar and the compression plate. This has required substantial force to back off the compression plate and disengage the clutch. Further, the metal driven discs have tended, as the shell rotates, to wobble giving the perception of quasi-engagement so that at times, even with the clutch "disengaged", motion is transmitted between the shell and the hub. This clearly is unacceptable.